Reciprocal altruism is a term found mostly in biology textbooks, specifically with regards to evolutionary biology. It is the principle that one being helps another because such altruism will benefit themselves (i.e. if you help a friend in need today, they will be more likely to help you tomorrow). Thus, these acts of compassion ultimately have selfish motives. This theory is used to explain why we (humans and other animals) often help our closest of kin, friends, and allies more than strangers and enemies.

The following videos are Robert Wright's TED talks, both of which focus on reciprocal altruism and the gradual expansion of nonzero sum relationships, so there is some redundancy. Still, both are very much worth watching, although, as he bluntly says, these are not the most uplifting/warm/fuzzy videos you will ever watch.

The Evolution of Compassion

"Robert Wright uses evolutionary biology and game theory to explain why we appreciate the Golden Rule (“Do unto others…”), why we sometimes ignore it and why there’s hope that, in the near future, we might all have the compassion to follow it."

How Cooperation (eventually) Trumps Conflict

"Author Robert Wright explains "non-zero-sumness," a game-theory term describing how players with linked fortunes tend to cooperate for mutual benefit. This dynamic has guided our biological and cultural evolution, he says -- but our unwillingness to understand one another, as in the clash between the Muslim world and the West, will lead to all of us losing the "game." Once we recognize that life is a non-zero-sum game, in which we all must cooperate to succeed, it will force us to see that moral progress -- a move toward empathy -- is our only hope."

Not to over-plug Wright's work, but he also has written three books that would be worth reading if you liked his talks: The Moral Animal, Nonzero, and The Evolution of God.

A paper by evolutionary psychologist Geoffrey Miller on the forces that (he believes) have produced and shaped our moral virtues.

In this article it mentions that "Neuroscientists, for example, have used neural imaging to show that acts of generosity light up the very pleasure and reward centers in your brain that are associated with sex and drugs." While this finding initially struck me as a win for morality, it then dawned on me that there is something more "sinister" going on: in order for this adaptation to arise, individuals who were altruistic must have survived and reproduced better than their rivals. Does this mean that our actions are motivated by self-interest? I suppose so. Acknowledging this "inescapable ugliness" from moment to moment is something that Dorothy Day grappled with.